General Description
The MAX6326/MAX6327/MAX6328/MAX6346/MAX6347/
MAX6348 microprocessor (µP) supervisory circuits moni-
tor the power supplies in µP and digital systems. These
devices provide excellent circuit reliability and low cost by
eliminating external components and adjustments when
used with 2.5V, 3V, 3.3V, and 5V powered circuits.
These circuits perform a single function: they assert a
reset signal whenever the VCC supply voltage declines
below a preset threshold, keeping it asserted for at least
100ms after VCC has risen above the reset threshold.
The only difference between the devices is their out-
put. The MAX6326/MAX6346 (push-pull) and MAX6328/
MAX6348 (open-drain) have an active-low reset output.
The MAX6327/MAX6347 have an active-high push-pull
reset output. All of these parts are guaranteed to be in the
correct state for VCC down to 1V. The reset comparator is
designed to ignore fast transients on VCC. Reset thresh-
olds are factory-trimmable between 2.2V and 4.63V, in
approximately 100mV increments. Twenty-one standard
versions are available. Contact the factory for availability
of nonstandard versions.
Ultra-low supply currents (1µA max for the MAX6326/
MAX6327/MAX6328) make these parts ideal for use in
portable equipment. All six devices are available in space-
saving SOT23 and SC70 packages.
Applications
Features
●Ultra-Low 1µA (max) Supply Current
(MAX6326/MAX6327/MAX6328)
●Precision Monitoring of 2.5V, 3V, 3.3V, and 5V
Power-Supply Voltages
●Reset Thresholds Available from 2.2V to 4.63V
●Fully Specified Over Temperature
●100ms (min) Power-On Reset Pulse Width
●Low Cost
●Available in Three Versions: Push-Pull RESET,
Push-Pull RESET, and Open-Drain RESET
●Power-Supply Transient Immunity
●No External Components
●3-Pin SC70/SOT23 Packages
●Pin Compatible with MAX803/MAX809/MAX810
Selector Guide appears at end of data sheet.
19-1294; Rev 5; 4/14
●Computers
●Intelligent Instruments
●Controllers
●Critical µP and µC
Power Monitoring
●Portable/Battery-Powered
Equipment
†The MAX6326/MAX6327/MAX6328/MAX6346/MAX6347/
MAX6348 are available in factory-set VCC reset thresholds
from 2.2V to 4.63V, in approximately 0.1V increments. Choose
the desired reset-threshold suffix from Table 1 and insert it in
the blank spaces following “R”. There are 21 standard ver-
sions with a required order increment of 2500 pieces. Sample
stock is generally held on the standard versions only (see the
Selector Guide). Required order increment is 10,000 pieces for
nonstandard versions (Table 2). Contact factory for availability.
All devices available in tape-and-reel only.
Devices are available in both leaded and lead-free packaging.
Specify lead-free by replacing “-T” with “+T” when ordering.
PART†TEMP. RANGE PIN-PACKAGE
MAX6326XR_ _-T -40°C to +85°C 3 SC70-3
MAX6326UR_ _-T -40°C to +85°C 3 SOT23-3
MAX6327XR_ _-T -40°C to +85°C 3 SC70-3
MAX6327UR_ _-T -40°C to +85°C 3 SOT23-3
MAX6328XR_ _-T -40°C to +85°C 3 SC70-3
MAX6328UR_ _-T -40°C to +85°C 3 SOT23-3
MAX6346XR_ _-T -40°C to +85°C 3 SC70-3
MAX6346UR_ _-T -40°C to +85°C 3 SOT23-3
MAX6347XR_ _-T -40°C to +85°C 3 SC70-3
MAX6347UR_ _-T -40°C to +85°C 3 SOT23-3
MAX6348XR_ _-T -40°C to +85°C 3 SC70-3
MAX6348UR_ _-T -40°C to +85°C 3 SOT23-3
1
2
3 VCC
(RESET) RESET
GND
( ) ARE FOR THE MAX6327/MAX6347.
MAX6326
MAX6327
MAX6328
MAX6346
MAX6347
MAX6348
SOT23-3/SC70-3
TOP VIEW
MAX6326/MAX6327/
MAX6328/MAX6346/
MAX6347/MAX6348
3-Pin, Ultra-Low-Power SC70/SOT
μP Reset Circuits
Pin Conguration
Ordering Information
Terminal Voltage (with respect to GND)
VCC .........................................................................-0.3V to +6V
RESET, RESET (push-pull) ......................-0.3V to (VCC + 0.3V)
RESET (open drain) ................................................-0.3V to +6V
Input Current (VCC) ...........................................................20mA
Output Current (RESET, RESET) ......................................20mA
Rate of Rise (VCC) ........................................................100V/µs
Continuous Power Dissipation (TA = +70°C)
3-Pin SC70 (derate 2.7mW/°C above +70°C) .............174mW
3-Pin SOT23 (derate 4mW/°C above +70°C) .............320mW
Operating Temperature Range ........................... -40°C to +85°C
Storage Temperature Range ............................ -65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
(VCC = full range, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = +25°C and VCC = 3V.) (Note 1)
Note 1: Overtemperature limits are guaranteed by design and not production tested.
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
VCC Range TA = 0°C to +70°C 1.0 5.5 V
TA = -40°C to +85°C 1.2 5.5
Supply Current ICC
MAX632_ only, VCC = 3.0V for VTH ≤ 2.93V,
VCC = 3.2V for VTH > 2.93V, no load 0.5 1.0 µA
VCC = 5.5V, no load 1.0 1.75
Reset Threshold VTH Table 1
TA = +25°C VTH -
1.5% VTH VTH +
1.5% V
TA = -40°C to +85°C VTH -
2.5% VTH VTH +
2.5%
Reset Threshold Tempco ∆VTH/°C 40 ppm/°C
VCC to Reset Delay VCC = VTH to (VTH - 100mV) 20 µs
Reset Active Timeout Period 100 185 280 ms
RESET Output Voltage
(MAX6326/MAX6328/
MAX6346/MAX6348)
VOL
ISINK = 1.6mA, VCC > 2.1V, reset asserted 0.3
V
ISINK = 100µA, VCC ≥ 1.2V, reset asserted 0.4
RESET Output Voltage
(MAX6326/MAX6346) VOH
ISOURCE = 500µA, VCC = 3.2V, MAX6326 only 0.8 · VCC
V
ISOURCE = 800µA, VCC = 4.5V, VTH ≤ 4.38V 0.8 · VCC
ISOURCE = 800µA, VCC = VTH(MAX), VTH ≥ 4.5V 0.8 · VCC
RESET Output Voltage
(MAX6327/MAX6347)
VOH
ISOURCE = 500µA, VCC ≥ 2.1V, reset asserted 0.8 · VCC
V
ISOURCE = 50µA, VCC ≥ 1.2V, reset asserted 0.8 · VCC
VOL
ISINK = 1.2mA, VCC ≥ 3.2V, reset not asserted,
MAX6327 only 0.3
ISINK = 3.2mA, VCC ≥ 4.5V, reset not asserted,
VTH ≤ 4.38V 0.4
ISINK = 3.2mA, VCC = VTH(MAX), VTH ≥ 4.5V 0.4
RESET Threshold
Hysteresis
MAX6326/MAX6327/MAX6328 6.3 mV
MAX6346/MAX6347/MAX6348 9.5
Open-Drain RESET
Output Leakage Current 0.1 µA
MAX6326/MAX6327/
MAX6328/MAX6346/
MAX6347/MAX6348
3-Pin, Ultra-Low-Power SC70/SOT
μP Reset Circuits
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Absolute Maximum Ratings
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these
or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect
device reliability.
Electrical Characteristics
(TA = +25°C, unless otherwise noted.)
PIN
NAME FUNCTION
MAX6326/MAX6346
MAX6328/MAX6348
MAX6327
MAX6347
1 1 GND Ground
2 — RESET
Active-Low Reset Output. RESET remains low while VCC is below the reset
threshold and for at least 100ms after VCC rises above the reset threshold.
RESET is open-drain on the MAX6328/MAX6348 and push-pull on the
MAX6326/MAX6346.
— 2 RESET Active-High Reset Output. RESET remains high while VCC is below the reset
threshold and for at least 100ms after VCC rises above the reset threshold.
3 3 VCC Supply Voltage
0
50
100
150
200
-40 0-20 20 40 60 80
POWER-DOWN RESET DELAY
vs. TEMPERATURE
MAX6326 toc02
TEMPERATURE (°C)
RESET DELAY (µs)
VOD = 200mV
VOD = 10mV
VOD = 100mV
VOD = 20mV
130
150
140
160
170
180
190
200
210
-40 0-20 20 40 60 80
POWER-UP RESET TIMEOUT
vs. TEMPERATURE
MAX6326 toc03
TEMPERATURE (°C)
POWER-UP RESET TIMEOUT (ms)
500
0
1100 1000
MAXIMUM TRANSIENT DURATION
vs. RESET THRESHOLD OVERDRIVE (SC70)
100
300
400
200
MAX6326 toc04
RESET THRESHOLD OVERDRIVE,
VTH - VCC (mV)
MAXIMUM TRANSIENT DURATION (µs)
10
0
0.3
0.2
0.1
0.4
0.5
0.6
0.7
0.8
0.9
1.0
-40 0-20 20 40 60 80
SUPPLY CURRENT vs. TEMPERATURE
MAX6326 toc01
TEMPERATURE (°C)
SUPPLY CURRENT (µA)
VCC = 3.3V
VCC = 5V
VCC = 1.2V
MAX6326/MAX6327/
MAX6328/MAX6346/
MAX6347/MAX6348
3-Pin, Ultra-Low-Power SC70/SOT
μP Reset Circuits
Maxim Integrated
│
3
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Typical Operating Characteristics
Pin Description
Applications Information
Interfacing to µPs with
Bidirectional Reset Pins
Since the RESET output on the MAX6328/MAX6348 is
open drain, these devices interface easily with micropro-
cessors (µPs) that have bidirectional reset pins, such as
the Motorola 68HC11. Connecting the µP supervisor’s
RESET output directly to the microcontroller’s (µC’s)
RESET pin with a single pull-up resistor allows either
device to assert reset (Figure 1).
Negative-Going VCC Transients
In addition to issuing a reset to the µP during power-up,
power-down, and brownout conditions, these devices are
relatively immune to short-duration, negative-going VCC
transients (glitches).
The Typical Operating Characteristics show the Maxi-
mum Transient Duration vs. Reset Threshold Overdrive
graph, for which reset pulses are not generated. The
graph shows the maximum pulse width that a negative-
going VCC transient may typically have when issuing a
reset signal. As the amplitude of the transient increases,
the maximum allowable pulse width decreases.
Figure 1. Interfacing to μPs with Bidirectional Reset Pins
‡Factory-trimmed reset thresholds are available in approximately 100mV increments with a 1.5% room-temperature variance.
Table 1. Factory-Trimmed Reset Thresholds‡
PART SUFFIX
RESET THRESHOLD VOLTAGE, VTH
(V)
TA =
+25°C
TA = -40°C to +85°C
MIN
TYP
MAX MIN MAX
MAX632_ _R
22 2.167 2.200 2.233 2.145 2.250
MAX632_
_R
23 2.285 2.320 2.355 2.262 2.375
MAX632_
_R
24 2.364 2.400 2.436 2.340 2.460
MAX632_
_R
25 2.462 2.500 2.537 2.437 2.562
MAX632_
_R
26 2.591 2.630 2.669 2.564 2.696
MAX632_
_R
27 2.660 2.700 2.741 2.633 2.768
MAX632_ _R
28 2.758 2.800 2.842 2.730 2.870
MAX632_
_R
29 2.886 2.930 2.974 2.857 3.000
MAX632_ _R
30 2.955 3.000 3.045 2.925 3.075
MAX632_
_R
31 3.034 3.080 3.126 3.003 3.150
MAX634_
_R
33 3.250 3.300 3.350 3.217 3.383
MAX634_
_R
34 3.349 3.400 3.451 3.315 3.485
MAX634_ _R
35 3.447 3.500 3.552 3.412 3.587
MAX634_
_R
36 3.546 3.600 3.654 3.510 3.690
MAX634_ _R
37 3.644 3.700 3.755 3.607 3.792
MAX634_
_R
38 3.743 3.800 3.857 3.705 3.895
RESET
GND
RESET
INPUT
MAX6328
MAX6348 MOTOROLA
68HCXX
µP
GND
VCC
VCC
VCC
MAX6326/MAX6327/
MAX6328/MAX6346/
MAX6347/MAX6348
3-Pin, Ultra-Low-Power SC70/SOT
μP Reset Circuits
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‡Factory-trimmed reset thresholds are available in approximately 100mV increments with a 1.5% room-temperature variance.
Table 2. Device Marking Codes and Minimum Order Increments
Table 1. Factory-Trimmed Reset Thresholds‡ (continued)
PART SUFFIX
RESET THRESHOLD VOLTAGE, VTH (V)
TA = +25°C TA = -40°C to +85°C
MIN TYP MAX MIN MAX
MAX634_ _R 39 3.841 3.900 3.958 3.802 3.997
MAX634_ _R 40 3.940 4.000 4.060 3.900 4.100
MAX634_ _R 41 4.038 4.100 4.161 3.997 4.202
MAX634_ _R 42 4.137 4.200 4.263 4.095 4.305
MAX634_ _R 43 4.235 4.300 4.364 4.192 4.407
MAX634_ _R 44 4.314 4.380 4.446 4.270 4.489
MAX634_ _R 45 4.432 4.500 4.567 4.387 4.612
MAX634_ _R 46 4.560 4.630 4.699 4.514 4.746
PART TOP MARK ORDER
INCREMENT (k)
SOT23 SC70
MAX6347_R46-T FZBW ACF 2.5
MAX6347_R45-T FZBV – 10
MAX6347_R44-T FZBU ACL 2.5
MAX6347_R43-T FZBT – 10
MAX6347_R42-T FZBS – 10
MAX6347_R41-T FZBR – 10
MAX6347_R40-T FZBQ – 10
MAX6347_R39-T FZBP – 10
MAX6347_R38-T FZBO – 10
MAX6347_R37-T FZBN – 10
MAX6347_R36-T FZBM – 10
MAX6347_R35-T FZBL – 10
MAX6347_R34-T FZBK – 10
MAX6347_R33-T FZBJ – 10
MAX6327_R31-T FMAA ACT 2.5
MAX6327_R30-T FNAA – 10
MAX6327_R29-T FLAA ACS 2.5
MAX6327_R28-T FKAA – 10
MAX6327_R27-T FJAA – 10
MAX6327_R26-T FIAA ACR 2.5
MAX6327_R25-T FHAA – 10
MAX6327_R24-T FGAA – 10
MAX6327_R23-T FFAA ACQ 2.5
MAX6327_R22-T EIAA AAI 2.5
PART TOP MARK ORDER
INCREMENT(k)
SOT23 SC70
MAX6346_R46-T FZBI ACO 2.5
MAX6346_R45-T FZBH – 10
MAX6346_R44-T FZBG ACK 2.5
MAX6346_R43-T FZBF – 10
MAX6346_R42-T FZBE – 10
MAX6346_R41-T FZBD – 10
MAX6346_R40-T FZBC – 10
MAX6346_R39-T FZBB – 10
MAX6346_R38-T FZBA – 10
MAX6346_R37-T FZAZ – 10
MAX6346_R36-T FZAY – 10
MAX6346_R35-T FZAX – 10
MAX6346_R34-T FZAW – 10
MAX6346_R33-T FZAV – 10
MAX6326_R31-T FDAA ACE 2.5
MAX6326_R30-T FEAA – 10
MAX6326_R29-T FCAA ACP 2.5
MAX6326_R28-T FBAA – 10
MAX6326_R27-T FAAA – 10
MAX6326_R26-T EZAA ACI 2.5
MAX6326_R25-T EYAA – 10
MAX6326_R24-T EXAA – 10
MAX6326_R23-T EWAA ACH 2.5
MAX6326_R22-T EHAA AAH 2.5
MAX6326/MAX6327/
MAX6328/MAX6346/
MAX6347/MAX6348
3-Pin, Ultra-Low-Power SC70/SOT
μP Reset Circuits
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Table 2. Device Marking Codes and Minimum Order Increments (continued)
Selector Guide (standard versions*)
*Sample stock is generally held on all standard versions.
PART TOP MARK ORDER
INCREMENT (k)
SOT23 SC70
MAX6348_R46-T SOT23 SC70
MAX6348_R46-T FZCK ACN 2.5
MAX6348_R45-T FZCJ – 10
MAX6348_R44-T FZCI ACM 2.5
MAX6348_R43-T FZCH – 10
MAX6348_R42-T FZCG – 10
MAX6348_R41-T FZCF – 10
MAX6348_R40-T FZCE – 10
MAX6348_R39-T FZCD – 10
MAX6348_R38-T FZCC – 10
MAX6348_R37-T FZCB – 10
MAX6348_R36-T FZCA – 10
MAX6348_R35-T FZBZ – 10
PART TOP MARK ORDER
INCREMENT (k)
SOT23 SC70
MAX6348_R34-T FZBY – 10
MAX6348_R33-T FZBX – 10
MAX6328_R31-T FVAA ACW 2.5
MAX6328_R30-T FWAA – 10
MAX6328_R29-T FUAA ACV 2.5
MAX6328_R28-T FTAA – 10
MAX6328_R27-T FSAA – 10
MAX6328_R26-T FRAA ACJ 2.5
MAX6328_R25-T FQAA – 10
MAX6328_R24-T FPAA – 10
MAX6328_R23-T FOAA ACU 2.5
MAX6328_R22-T EJAA AAJ 2.5
PART
NOMINAL
V
TH
(V)
MAX634_
_R46-T
4.63
MAX634_
_R44-T
4.38
MAX632_ _R31-T
3.08
MAX632_ _R29-T
2.93
MAX632_ _R26-T
2.63
MAX632_ _R23-T
2.32
MAX632_ _R22-T
2.20
PACKAGE
TYPE
PACKAGE
CODE
OUTLINE
NO.
LAND
PATTERN NO.
3 SC70 X3-2 21-0075 90-0208
3 SOT23 U3-1 21-0051 90-0179
MAX6326/MAX6327/
MAX6328/MAX6346/
MAX6347/MAX6348
3-Pin, Ultra-Low-Power SC70/SOT
μP Reset Circuits
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Chip Information
TRANSISTOR COUNT: 419
Package Information
For the latest package outline information and land patterns
(footprints), go to www.maximintegrated.com/packages. Note
that a “+”, “#”, or “-” in the package code indicates RoHS status
only. Package drawings may show a different suffix character, but
the drawing pertains to the package regardless of RoHS status.
REVISION
NUMBER
REVISION
DATE DESCRIPTION PAGES
CHANGED
0 12/05 Initial release —
1 4/14 No /V OPNs; removed Automotive reference from Applications section 1
Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses
are implied. Maxim Integrated reserves the right to change the circuitry and specications without notice at any time. The parametric values (min and max limits)
shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.
MAX6326/MAX6327/
MAX6328/MAX6346/
MAX6347/MAX6348
3-Pin, Ultra-Low-Power SC70/SOT
μP Reset Circuits
© 2014 Maxim Integrated Products, Inc.
│
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Revision History
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MAX6348UR46+T MAX6348XR42+T MAX6326UR22+T MAX6326UR23+T MAX6326UR24+T MAX6326UR25+T
MAX6326UR26+T MAX6326UR27+T MAX6326UR28+T MAX6326UR29+T MAX6326UR30+T MAX6326UR31+T
MAX6326XR22+T MAX6326XR23+T MAX6326XR24+T MAX6326XR25+T MAX6326XR26+T MAX6326XR27+T
MAX6326XR28+T MAX6326XR29+T MAX6326XR30+T MAX6326XR31+T MAX6327UR22+T MAX6327UR23+T
MAX6327UR24+T MAX6327UR25+T MAX6327UR26+T MAX6327UR27+T MAX6327UR28+T MAX6327UR29+T
MAX6327UR30+T MAX6327UR31+T MAX6327XR22+T MAX6327XR23+T MAX6327XR24+T MAX6327XR25+T
MAX6327XR26+T MAX6327XR28+T MAX6327XR29+T MAX6327XR30+T MAX6327XR31+T MAX6328UR22+T
MAX6328UR23+T MAX6328UR24+T MAX6328UR25+T MAX6328UR26+T MAX6328UR27+T MAX6328UR28+T
MAX6328UR29+T MAX6328UR30+T MAX6328UR31+T MAX6328XR22+T MAX6328XR23+T MAX6328XR24+T
MAX6328XR25+T MAX6328XR26+T MAX6328XR27+T MAX6328XR28+T MAX6328XR29+T MAX6328XR30+T
MAX6328XR31+T MAX6346UR33+T MAX6346UR34+T MAX6346UR35+T MAX6346UR36+T MAX6346UR37+T
MAX6346UR38+T MAX6346UR39+T MAX6346UR40+T MAX6346UR41+T MAX6346UR42+T MAX6346UR43+T
MAX6346UR44+T MAX6346UR45+T MAX6346UR46+T MAX6346XR33+T MAX6346XR34+T MAX6346XR35+T
MAX6346XR36+T MAX6346XR37+T MAX6346XR38+T MAX6346XR39+T MAX6346XR40+T MAX6346XR41+T
MAX6346XR42+T MAX6346XR43+T MAX6346XR44+T MAX6346XR45+T MAX6346XR46+T MAX6347UR33+T
MAX6347UR34+T MAX6347UR35+T MAX6347UR36+T MAX6347UR37+T MAX6347UR38+T MAX6347UR39+T
MAX6347UR40+T MAX6347UR41+T MAX6347UR42+T MAX6347UR43+T
